1 / 55

UCLA NS 172

Neuroimaging and MRI Physics. Other Resources. These slides were condensed from several excellent online sources. Credit is given where appropriate. If you would like a more thorough introductory review of MR physics, see the following:1. Robert Cox's slideshow, (f)MRI Physics with Hardly Any Mat

levana
Télécharger la présentation

UCLA NS 172

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. UCLA NS 172/272/Psych 213 Brain Mapping and Neuroimaging Instructor: Ivo Dinov, Asst. Prof. In Statistics and Neurology University of California, Los Angeles, Winter 2006 http://www.stat.ucla.edu/~dinov/ http://www.loni.ucla.edu/CCB/Training/Courses/NS172_2006.shtml

    2. Neuroimaging and MRI Physics

    3. Other Resources

    4. References “Foundation of Medical Imaging,” Z.H. Cho, J.P. Jones, M. Singh, John Wiley & Sons, Inc., New York 1993, ISBN 0-471-54573-2 “Principles of Medical Imaging,” K.K. Shung, M.B. Smith, B. Tsui, Academic Press, San Diego 1992, ISBN 0-12-640970-6 “Handbook of Medical Imaging,” Vol. 1, Physics and Psychophysics, J. Beutel, H. L. Kundel, R. L. Van Metter (eds.), SPIE Press 2000, ISBN 0-8194-3621-6 Brain Mapping: The Methods, by Arthur W. Toga & John Mazziotta

    5. Introduction: What is Medical Imaging? Goals: Create images of the interior of the living human body from the outside for diagnostic purposes. Biomedical Imaging is a multi-disciplinary field involving Physics (matter, energy, radiation, etc.) Math (linear algebra, calculus, statistics) Biology/Physiology Engineering (implementation) Computer science (image reconstruction, signal processing, visualization)

    6. BMI methods: X-Ray imaging Year discovered: 1895 (Röntgen, NP 1905) Form of radiation: X-rays = electromagnetic radiation (photons) Energy / wavelength of radiation: 0.1 – 100 keV / 10 – 0.01 nm (ionizing) Imaging principle: X-rays penetrate tissue and create shadowgram of differences in density. Imaging volume: Whole body Resolution: Very high (sub-mm) Applications: Mammography, lung diseases, orthopedics, dentistry, cardiovascular, GI, neuro

    7. Electromagnetic Spectrum

    8. Radio wave devices

    9. BMI methods: X-Ray Computed Tomography Year discovered: 1972 (Hounsfield, NP 1979) Form of radiation: X-rays Energy / wavelength of radiation: 10 – 100 keV / 0.1 – 0.01 nm (ionizing) Imaging principle: X-ray images are taken under many angles from which tomographic ("sliced") views are computed Imaging volume: Whole body Resolution: High (mm) Applications: Soft tissue imaging (brain, cardiovascular, GI)

    10. Electromagnetic Spectrum

    11. BMI methods: Nuclear Imaging (PET/SPECT) Year discovered: 1953 (PET), 1963 (SPECT) Form of radiation: Gamma rays Energy / wavelength of radiation: > 100 keV / < 0.01 nm (ionizing) Imaging principle: Accumulation or "washout" of radioactive isotopes in the body are imaged with x-ray cameras. Imaging volume: Whole body Resolution: Medium – Low (mm - cm) Applications: Functional imaging (cancer detection, metabolic processes, myocardial infarction)

    12. Electromagnetic Spectrum – PET/SPECT

    13. Functional Brain Imaging - Positron Emission Tomography (PET)

    14. Functional Brain Imaging - Positron Emission Tomography (PET)

    15. Functional Brain Imaging - Positron Emission Tomography (PET)

    16. BMI methods: Magnetic Resonance Imaging Year discovered: 1945 (Bloch & Purcell) 1973 (Lauterburg, NP 2003) 1977 (Mansfield, NP 2003) 1971 (Damadian, SUNY DMS) Form of radiation: Radio frequency (RF) (non-ionizing) Energy / wavelength of radiation: 10 – 100 MHz / 30 – 3 m (~ 10-7 eV) Imaging principle: Proton spin flips are induced, and the RF emitted by their response (echo) is detected. Imaging volume: Whole body Resolution: High (mm) Applications: Soft tissue, functional imaging

    17. Electromagnetic Spectrum

    18. BMI methods: Ultrasound Imaging Year discovered: 1952 (Norris, clinical: 1962) Form of radiation: Sound waves (non-ionizing) Frequency / wavelength of radiation: 1 – 10 MHz / 1 – 0.1 mm Imaging principle: Echoes from discontinuities in tissue density/speed of sound are registered. Imaging volume: < 20 cm Resolution: High (mm) Applications: Soft tissue, blood flow (Doppler)

    19. Electromagnetic Spectrum

    20. BMI methods: Optical Tomography Year discovered: 1989 (Barbour) Form of radiation: Near-infrared light (non-ionizing) Energy / wavelength of radiation: ~ 1 eV/ 600 – 1000 nm Imaging principle: Interaction (absorption, scattering) of light w/ tissue. Imaging volume: ~ 10 cm Resolution: Low (~ cm) Applications: Perfusion, functional imaging

    21. BMI methods: Optical Tomography

    22. Electromagnetic Spectrum

    23. Recipe for MRI

    24. History of NMR

    25. History of fMRI

    26. Necessary Equipment

    27. The Big Magnet

    28. Magnet Safety - The whopping strength of the magnet makes safety essential. Things fly – Even big things!

    29. Subject Safety

    30. Protons

    31. What nuclei exhibit this magnetic moment (and thus are candidates for NMR)?

    32. Outside magnetic field – random orientation In Mag Field - Protons align with field

    33. Radio Frequency

    34. Larmor Frequency

    35. RF Excitation

    36. Cox’s Swing Analogy

    37. Relaxation and Receiving

    38. T1 and TR

    39. Spatial Coding: Gradients

    40. How many fields are involved after all?

    41. Precession In and Out of Phase

    42. T2 and TE

    43. Echos

    44. T1 vs. T2

    45. T1 vs. T2 – contrast and noise

    46. Properties of Body Tissues

    47. MRI of the Brain - Sagittal

    48. MRI of the Brain - Axial

    49. MRI Quality Determinants

    50. MRI Quality Determinants – period = 1/frequency

    51. K-Space – an MRI literature fancy name for Fourier space

    52. A Walk Through (sampling from ) K-space

    53. T2*

    54. Susceptibility

    55. Signal-to-Noise Ratio (SNR)

    56. Motion Correction

More Related